Ok. I am going to layout my thoughts here, as well as what I have found researching:
First of all, one interesting thing that I learned while reading about this species on wikipedia is that it was one of the two species of marsupials in which both genders have a pouch. The other being the opossum.
My overall thought is that the Tasmanian Tiger is unfortunately extinct. I think this for two main reasons. The first of these reasons is that the Tasmanian Tiger was, at one point, on Mainland Australia. But, according to the article I found on JStor (citations at the bottom), the Tasmanian Tiger disappeared from mainland Australia likely due to the introduction of Dingos to the environment.
Responsibility for the decline and extinction of the thylacine on mainland Australia was attributed simplistically and almost entirely to introduction of the dingo (Canis familiaris dingo)(1331).
I think the fact that it first disappeared from Mainland Australia demonstrates that it was not able to adapt to the introduction of competing predators, or to any other large scale change to its environment.
In addition to this, the article states that the early Western settlers, and even later Australian government, were on a campaign to remove it from existence.
The thylacine was demonized by European explorers and settlers because of its superficial resemblance to other predators, such as the wolf (Canis lupus) in Europe and tiger in Asia (1332).
Ultimately, the death sentence for the thylacine is laid squarely at the doorstep of the Australian Parliament, which passed a bill in 1886 making it the policy of the Australian government to eliminate the thylacine from Tasmania (1332).
I think the fact that the government and settlers actively sought to eradicate it combined with its previously demonstrated inability to adapt is enough to believe that they were unfortunately successful in their endeavor, and that it is now extinct.
The video footage was not clear enough to convince me otherwise, but perhaps someone else will make a point that I have not thought of. Looking forward to reading the comments!
Leidy, Robert A. “Myth Meets Reality in Tasmania: The Fall and Rise of the Pouched Thing with a Dog Head.” Conservation Biology, vol. 19, no. 4, 2005, pp. 1331–1333. JSTOR, www.jstor.org/stable/3591323. Accessed 24 Mar. 2020.